Knoop Hardness (HK)
Calculate the Knoop hardness, HK = 14.229 × F ÷ d², from the load F (kgf) and the long diagonal d (mm) of the elongated rhombic indentation left by a Knoop diamond indenter. The result, in kgf/mm² (HK), is used mainly for microhardness of brittle materials, coatings, glass and ceramics, and thin samples: the Knoop's elongated, shallow indentation measures narrow layers and hardness gradients better than Vickers and is less sensitive to microcracking. Enter the load and the long diagonal of the indentation.
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Dureza Knoop (HK)
A dureza Knoop é uma variação da microdureza criada para situações em que o Vickers tem limitações. Seu penetrador de diamante é uma pirâmide alongada e assimétrica, que deixa uma impressão em forma de losango bem comprido (a diagonal maior é cerca de 7 vezes a menor). A dureza vem da carga dividida pela área projetada: HK = 14,229 × F ÷ d², com F em kgf, d a diagonal maior em mm. O formato alongado traz três vantagens. Primeiro, a impressão é rasa (menos profunda que a Vickers para a mesma carga), ideal para revestimentos finos, camadas superficiais e amostras delgadas, sem o substrato influenciar. Segundo, mede-se apenas a diagonal longa, o que dá boa resolução para mapear gradientes de dureza em distâncias pequenas. Terceiro, em materiais frágeis como vidros e cerâmicas, a impressão Knoop é menos propensa a gerar microtrincas que falseariam a leitura. Por isso o Knoop é o método preferido em metalografia de materiais duros e quebradiços e no estudo de filmes e tratamentos de superfície. Informe a carga e a diagonal maior da impressão.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.